chore: deprecate v5

docs(changelog): update changelog for release 6.1.1

deprecating v4

deprecate v3

Merge pull request #499 from tuneinsight/squash

v6.1.0

Merge pull request #492 from tuneinsight/he-collapse

v6.0.0

adapt changelog to v6

Merge pull request #420 from tuneinsight/fix_bgv_eval_shallowcopy

Fix bgv eval shallowcopy

Merge pull request #417 from tuneinsight/dev_fix_benchmarks

Dev fix benchmarks

Merge pull request #379 from tuneinsight/dev_release_v4.2.0

Release v5